“This is a fully new transmission concept which will advance the development of electric vehicles.”

According to Oerlikon Graziano, the 4SED “boasts increased efficiency, seamlessly smooth shifting and a scalable design making it suitable for a wide range of vehicle types.”

Paolo Mantelli, Head of Oerlikon Graziano Performance Automotive, describes the 4SED is detail:

“The design of the gearbox is very simple. The transmission’s unique configuration uses two input shafts, each driven by its own electric motor. The two motors replace the twin clutches and the synchronizers, allow pre-selection of the next gear before the previous one has been disengaged, and can synchronize shaft speeds. The use of the traction motors also permits a reduced set of software algorithms compared to a normal automated gearbox, and since there are no hydraulics, there is no need for valve control. It is seamless, it is clutch less, it needs no synchronizer and is truly innovative!”

So far, only a demonstration Mercedes Vito has been fitted with the 4SED. Oerlikon Graziano hopes to commercialize the trans in 2014. Of the demonstrator Vito, which has been drive by “customers,” the response is that “the shifting function is very impressive, there is no feeling of torque interruption and they are very smooth,” according to Oerlikon Graziano.

As in any design, ICE or BEV a transmission multiplies torque and widens the operational range of the drive train, specifically the power source. In an electric car you will save at Hwy speeds by keeping the RPM lower where an electric motor has better response. Remember an electric motor has its best “throttle” response at low RPM and actually flattens out as the speed increases. This is just the opposite of an ICE. This has the effect of using about 15% less electricity. This value is from the numbers I have read about not from personal experience. From a city perspective just as in an ICE car you will get better acceleration due to the torque being multiplied. Perhaps smaller motors doing the same 0-60 times or smaller motors with the same times but using less power. The design would specify how much smaller it can be and how much you would save. The big question is would the savings be worth the added complexity, maintenance and cost. Unknown for now as nothing was written up about the cost. As a guess this would be most useful in bus or truck applications that are beginning to appear. The added… Read more »

Advance EVs? by adding needless complexity weight and cost? I think not.
The only place where a multispeed gearbox makes sense for an EV is high performance racer or maybe a special low speed tow or terrain capability.

Speaking of which, can a Nissan Leaf pull up the steepest san francisco roads? they have a crazy road there where the side walk is stairs which could potentially be a problem for a single speed car that doesn’t have fast acceleration.
Not that I would really change the engineering of a car to suit a single road in the world.

My experience of driving my Leaf is it chews up hills like they’re not even there. I can’t speak for San Francisco but there’s a steep hill near here that ICE cars struggle with. It’s a shame there’s a sharp bend on that road otherwise I’d be able to really surprise some people following me!

Not sure what EVs need 4 speeds for. One extra speed sounds useful for high speeds though. Tesla failed in its attempt to do a 2 speed transmission and as a result their cars have top speeds that are somewhat low for their class.